Air conditioning systems for buildings comprise a thermostat that communicates temperature information to a master controller that uses this information to energize and de-energize an appropriate climate control unit, such as an air-heating unit or an air-cooling unit. Typically, the thermostat, air-heating unit, and master controller are inside the building and the air-cooling unit is outside the building. Signals between the air-cooling unit and the master controller are transmitted through wires that run from the master controller, through walls of the building, and outside to the air-cooling unit. This necessitates planning and coordinating of where and how the wire will be run when a new building is constructed, or when the air conditioning system is initially installed in an existing building. Moreover, these wires are susceptible to breaks, cracks, corrosion, or attack from various critters that may be living in the walls, such as for example, mice and rats. Once a wire has been severed, replacing it can be a very difficult and expensive process because the wire or wires are often not easily accessible, thus making it very difficult to determine the exact location of the severed part of a wire, often requiring replacing the entire length of wire.